Dave's 17-year-old and eldest daughter has been brought up knowing how to shoot, hunt, fight, and utilize other survivalist techniques, just in case she ever has to leave the Republic. Shawna completely believes in her father's omnipotence. She is a very anxious, high-strung girl.
Shawna, as curator for the Museum of Dave, handles the museum budget. If you pass a Speech check, you can sell her any of the junk you've found in the Wasteland for its base value to her. The budget of the museum is 700 caps, but you should still be able to bleed her wallet dry easily. The items you sell her will not actually be displayed in the museum.